Using Fiber-Optic-Enabled Coiled Tubing to Quantify Fluid Placement and Optimize Stimulation Effectiveness During Matrix Stimulation Treatments in Carbonate Reservoirs

Abstract

When performing matrix stimulation treatments, coiled tubing (CT) is a preferred placement technique due to the ability to spot fluid in front of the target zone(s). This method becomes a key solution when formation heterogeneities require a very selective fluid placement strategy.In today's industry, the most common approach is to design a treatment with volumes of stimulation and diverter fluids that are determined largely based on local practices. Often, it amounts to targeting a uniform stimulation, thus requiring a predefined amount of treatment fluid per length of total pay zone. That approach, although widely used and accepted, may not necessarily yield an optimum stimulation.We present an alternative technique that relies on the accurate quantification of fluid placement along the formation in order to define the respective volumes of stimulation and diverter fluids to be pumped. This method relies on the analysis of the distributed temperature sensing (DTS) data recorded by a fiber-optic line enclosed inside the CT and data processing through a fast interpretation algorithm to yield a zonal coverage profile. During a job, DTS data corresponding to the preflush can be used to estimate the initial placement distribution across the pay zone. This allows stimulation engineers to determine the best strategy for the subsequent well stimulation treatment, including fluid volumes and placement sequence. After every major pumping stage, a new DTS analysis assesses how the formation reacted to the treatment, improving placement strategy.This method has been used in multiple matrix stimulation treatments of injector and producer wells. The described innovative approach allows engineers to make more informed decisions between stages, optimizing fluid resources, fluid placement and, ultimately, stimulation effectiveness. It also leads to noteworthy advantages when designing new acidizing treatments, as companies can build on previous experience from similar wells and fields.

Advanced Understanding of Matrix Stimulation Treatments Through In-Job and Post-Job Evaluation of Real-Time Downhole Measurements with Coiled Tubing: A Case Study

“…The workflow detailed in Ramondenc and Baez (2013) describes the steps to follow in order to leverage the use of DTS acquisition through the course of a carbonate acidizing treatment in order to optimize fluid placement. A summary of this workflow is given below:…”

An Innovative Methodology for Real-Time Control and Optimization of Dual Injection Increases Efficiency of Carbonate Stimulation in Horizontal Openhole Water Injectors

“…However, it usually requires large displacement volumes and/or might induce high friction pressures to reach the targeted interval, especially in extended reach horizontal wells. Meanwhile, CT allows a deeper reach with targeted, smaller volumes, as well as the possibility to better spot the treatment, but at the price of somewhat lower pumping rates (Kalfayan and Martin 2009;Ramondenc and Baez 2013).…”

“…It has also provided additional pieces of information about any downhole events occurring during matrix stimulation interventions, so that one can better close the design-executionevaluation loop (Ahmed et al 2014). Many studies are today available to demonstrate not only how DTS can be used to understand where treatment fluids go during a carbonate acidizing treatment (Glasbergen et al 2009;Al-Najim et al 2012;Tan et al 2012;Tardy et al 2012), but also how this measurement can be leveraged to optimize the intervention (Ramondenc and Baez 2013;Inda Lopez et al 2014). Although a step forward towards realizing better fluid placement during an intervention, those methods still rely on the effectiveness of the diversion mechanisms used to control fluid coverage.…”

“…The methodology presented thereafter introduces a new downhole flow measurement tool that complements the typical workflow leveraging CT real-time fiber-optic telemetry for the evaluation of fluid placement (Ramondenc and Baez 2013). Although the scope of this work specifically focuses on long horizontal openhole water injectors, the methodology presented here can further be extended to other settings, rock types, and well configurations.…”

2 1/8-in. Intelligent Coiled Tubing System Improves Operational Efficiency

“…Among those, the most advanced ones employ a 1/8-in. insulated electrical conductor (Taggart et al 2010(Taggart et al , 2011Oberascher et al 2012;Livescu et al 2015) or an optical fiber (Aviles et al 2011;Garcia et al 2011;Ramondenc and Baez 2013;Ahmed et al 2014a,b;Gorgi et al 2014;Ramondenc et al 2014;Webb et al 2014;Medina et al 2015). The BHAs for both systems were designed to meet similar requirements.…”